Probiotics May Help Reduce Blood Sugar Levels

A cup of greek yogurt
(Image credit: mama_mia/

NEW ORLEANS — The microbes that live in your gut may play a surprising role in your blood sugar levels, a small new study from Canada finds.

The study involved people who were following the DASH diet, which is recommended for people with high blood pressure. The people on this diet who also consumed probiotics, which are considered "good" bacteria, had a decrease in several measures of blood sugar levels over a three-month period, according to the findings. People with consistently high blood sugar levels may or may not go on to be diagnosed with diabetes; a diagnosis can depend on the results of several tests.

Although more research is needed, the findings suggest that adding probiotics to the DASH diet could be used in the future to help protect against diabetes, said Arjun Pandey, a researcher at the Cambridge Cardiac Care Centre in Ontario and the author of the study. [8 Tips to Be a Probiotic Pro]

Pandey presented his findings here on Sunday (Nov. 13) at the American Heart Association's Scientific Sessions annual meeting. The findings have not been published in a peer-reviewed journal.

In the study, 80 people with high blood pressure were placed on either the DASH diet or the DASH diet plus probiotic-rich foods. About 15 percent of the participants had prediabetes, Pandey noted, which means their blood sugar levels were elevated but were not considered high enough to warrant a diagnosis of diabetes.

The DASH diet, which stands for Dietary Approaches to Stop Hypertension, is one of the most effective non-drug-related methods for improving certain aspects of heart health, including lowering blood pressure, Pandey told Live Science.

The people in the study who added the probiotics to their diet did so by replacing certain components of the DASH diet with probiotic-rich components, Pandey said. For example, instead of just consuming any type of low-fat dairy product, as recommended by the DASH diet, a person could eat a low-fat probiotic yogurt, he said.

Before the study participants started the diets, the researchers measured the people's hemoglobin A1C, fasting blood sugar levels and blood pressure. They took the measurements again at the end of the study.

The hemoglobin A1C test measures how much hemoglobin, a protein found in red blood cells, is linked with sugar molecules, according to the American Diabetes Association (ADA). The more sugar molecules that are present in a person's blood, the more linked-up hemoglobin molecules there are, the ADA says. The fasting blood sugar test measures a person's blood sugar levels before he or she has eaten anything that day.

Before the diets began, there were no differences in the measurements between the two groups, Pandey said. [Don't Be Fooled: 5 Probiotics Myths]

After three months, both groups had similarly lower blood pressure measurements, Pandey said. In other words, adding probiotics did not appear to be associated with a change in blood pressure, specifically.

But adding probiotics did have a significant link with the participants' blood sugar measurements, Pandey said. 

At the three-month mark, the people who had followed only the DASH diet (with no added probiotics) had lowered their hemoglobin A1C, on average, by 3.4 percent. In comparison, those who had followed the DASH diet plus probiotics had lowered their hemoglobin A1C, on average, by 8.9 percent.

Adding probiotics to the DASH also had a stronger link with the participants' fasting blood sugar levels, according to the study. The DASH-plus-probiotics group lowered their fasting blood sugar levels by 10.7 percent, on average, compared with an average reduction of 3.3 percent in the group that followed only the DASH diet. 

Although the study doesn't prove a cause-and-effect link between probiotics and lower blood sugar levels, one possible explanation for how probiotics could lower blood sugar levels is through a compound called butyrate, Pandey said. In the gut, certain bacteria produce butyrate, which may play a role in insulin sensitivity, he said. When insulin sensitivity is higher, the body does a better job of absorbing sugar from the blood, therefore lowering blood sugar levels.

Pandey noted that there were several limitations to the study, including the small number of study participants and the short duration of the study. To validate the findings, the research should be carried out in a larger, more diverse group of people for a longer time period, Pandey said.

Originally published on Live Science.

Sara G. Miller
Staff Writer
Sara is a staff writer for Live Science, covering health. She grew up outside of Philadelphia and studied biology at Hamilton College in upstate New York. When she's not writing, she can be found at the library, checking out a big stack of books.